package tool;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.MessageDigest;

public class MD5Filter {
	
    public static String getMd5ByFile(File file) throws FileNotFoundException {
        String value = null;	   
        FileInputStream in = new FileInputStream(file);
	try {
	    MappedByteBuffer byteBuffer = in.getChannel().map(FileChannel.MapMode.READ_ONLY, 0, file.length());
	    MessageDigest md5 = MessageDigest.getInstance("MD5");
	    md5.update(byteBuffer);
	    BigInteger bi = new BigInteger(1, md5.digest());
	    value = bi.toString(16);
	} catch (Exception e) {
	    e.printStackTrace();
	} finally {
			if(null != in) {
	            try {
		        in.close();
		    } catch (IOException e) {
		        e.printStackTrace();
		    }
	    }
	}
	return value;
    }

}